1. Field of the Invention
The present invention relates generally to hinge hardware that have plural axes. More particularly, the present invention relates to a corner hinge assembly for use on a display case that has a heavy door (such as a thick glass door typically used on a museum display case) which opens outwardly around one of the door's vertical edges and wherein the configuration of the corner hinge assembly is such that it hidden from view within the specialized supporting structure for the display case.
2. Description of the Related Art
A heavy door or door panel, such as the thick glass door found on museum display cases or cabinets, requires a strong hinge on the vertical edge of the cabinet about which the door is to swing or move to provide support for the door or panel as it is moved between an opened and a closed position. It would also be beneficial if this hinge could be designed so that it would not require the opening door to move outside of or to the side of the cabinet's vertical edge about which the door is to move as such a hinge would enable the door to be fully opened even in the situation where there is a vertical wall that adjoins the cabinet on this vertical edge. Additionally, there are other situations, in which for security or visual aesthetic purposes, it would be beneficial to also have such a hinge be configured such that it is concealed and not readily accessible.
U.S. Pat. No. 1,412,107 to Evans, Jr. discloses a garage door hinge having arms equidistant from the center and side edge of the door. U.S. Pat. No. 1,817,773 to Sipe discloses a concealed door hinge having a dual pair of pivots with connecting links. During the opening of the door, the hinged side travels behind the face line of the mounting surface on the cabinet.
Lefevre, in U.S. Pat. No. 2,008,256 discloses a concealed door hinge for an automobile which does not permit the hinge to be mounted between the door and the structure. One part of the hinge is mounted on the edge of the door and the other part is mounted on the doorjamb which must be adjacent to the edge of the door in the closed position. The links are relatively lightweight and direct the throwout or offset of the door while not carrying a substantial part of the load.
U.S. Pat. No. 2,771,042 to Deaton discloses a hinge for bank vault doors in which the main hinge plate carries the entire weight of the door and the link stabilizes the door. The door moves between the closed and opened positions by maintaining the door parallel to the closed position without rotation of the door. U.S. Pat. No. 4,135,273 to Holmes discloses a hinge with interfitting locking means in which the door rotates about a single pivot point.
U.S. Pat. No. 4,848,244 to Bennett discloses a pair of fold-away hinges to support a horizontal work surface which can be folded down when not in use. A slot is provided in which one of the pivots slides during raising and lowering of the work surface. U.S. Pat. No. 5,704,095 to Guenschel discloses a hinge which permits pivotal movement of the door or panel in a manner such that the door moves, as it opens, towards the center of the front of the display case and therefore it does not come into contact with a wall that directly abuts the vertical edge of the display case about which the door is opening. This hinge has the same inventor as the present invention and the information in U.S. Pat. No. 5,704,095 is included herein by reference and its disclosed hinge is referred to herein as a “Vista” hinge.
Despite this prior art, there is a need for an improved hinge assembly for use on display cases having glass top panels and which utilize heavy doors when it is desired to place the vertical edge about which the case's door is to open tight against an adjoining vertical wall and, while at the same time, for security and visual aesthetic reasons, concealing the hinge so that it cannot be seen by one who examines the exterior surface of the display case.